Horizontally expandable, silage storage bags are commonly used as an alternative to permanent feed storage structures such as barns and silos. From an economic standpoint, an expandable plastic storage bag is preferable to a more elaborate, permanent structure. Further, the expandable bags are more easily loaded with feed than permanent structure and the silage stored therein is readily accessible for use, for example using a small tractor with a front bucket to unload the feed.
An exemplary prior art bagger is described in U.S. Pat. No. 5,878,552 (which patent is incorporated herein in its entirety by reference), to Paul Wingert, the present applicant. A tractor-powered bag-loading apparatus is disclosed in association with an expandable bag. A backstop is located at the filled end of the bag and has attached thereto laterally spaced cables which extend forward to rotatable cable drums on the bagger machine. The drums are yieldably braked and, under a predetermined force applied to the cables, release the cable to allow movement of the bag-loading apparatus and tractor away from the filled end of the bag as it is filled. The bag is filled by a toothed rotor which propels silage through a tapered tunnel and into the bag inlet. The tapered tunnel described in U.S. Pat. No. 5,878,552 provides a smooth, more evenly filled bag.
The bag for use with such bagging machines is manufactured and delivered in a pleated shape, i.e., folded into an accordion-bellows-type shape. Typically, a bag having a nominal ten-foot-diameter (approximately 3 meters diameter, or 9.6 meters circumference) and a 300-foot length (approximately 90 meters length) will be folded to a 10-foot-diameter (about 3 meters) ring about one foot (about 0.3 meter) long and 1 foot (about 0.3 meter) thick. To start the loading operation, this bag-ring is pre-loaded around the tunnel, and the pleats are unfolded one at a time as the bag is deployed and filled with feed stock. Once any portion of the bag fills with feed, that portion becomes very heavy, and does not move. Thus the bagger machine itself is propelled along the ground in front of the bag being filled.
FIG. 1 shows a side view of a prior-art bagger 100 (also called feed-bagging machine 100) such as shown and describes in U.S. Pat. No. 5,878,552 by the inventor of the present invention, hereby incorporated by its entirety by reference. The feed bagger is not pulled; rather, the pressure from the feed filling the bag pushes the bagger 100 and the tractor (not shown) that is powering it (bagger 100) ahead at a rate equal to the filling rate of bag 99. A steel cable between bagger 100 and a backstop (not shown, but which is to the right of the apparatus and bag shown in FIG. 1) is yieldably held by a disk-brake mechanism. This ensures the feed is compacted before the bagger is allowed to advance. A rotor 130 having multiple teeth 131, and powered by a power-take-off (PTO) shaft 133 from the tractor that powers bagger 100, forces feed 98 up and back into a tunnel 250. In some embodiments, tunnel 250 is a long tapered tunnel such as described in U.S. Pat. No. 5,878,552.
Movable upper bag bracket 125 is used to lift the folded bag 99 into place on the outside of tunnel 250, and supports/holds the folded bag 99 at the front end of the top of tunnel 250 as it unfolds from the inside of the folded bag. Lower bag tray 120 is tilted up at its trailing edge, supported at its front edge by brackets 121, and yieldably supported at its back edge by spring-and-chain (not shown, but which can have its force adjusted by setting various chain links of the chain onto a fixed hook at the top). The feed is dropped into hopper 139. Such a bagger 100 has a tunnel 250 that provides some support for bag 99 as it unfolds, but which has side walls along which the bag unfolds that are ovoid such that the bag is stretched slightly and then released as it passes over tunnel 250 in the direction of travel of the bagger 100. The bagger tunnel provides some back-pressure to the feed which thus extrudes into the bag rearward at a substantially constant pressure.
There are numerous problems that one contends with using previous bagging structures. For example, there is a safety problem caused by feed that bridges within the tapered hopper. Persons may be tempted to unclog the hopper by stomping or otherwise inserting an arm or a leg thus risking being sucked through and shredded by the primary compression mechanism.
Conventional baggers also suffer from an inability to adequately compact feed in the upper portion of the tunnel, thus leaving the feed in the lower bag highly compacted and the feed in the upper bag only moderately compacted.